<%@ tag import="java.math.BigInteger" %>
<%@attribute name="n" type="java.lang.Integer" required="true" %>
<%@variable name-given="outcome" variable-class="java.math.BigInteger" scope="AT_BEGIN" %>
<%! public BigInteger fun(int n){
    return n>1?fun(n-1).multiply(BigInteger.valueOf(n)):BigInteger.valueOf(n);
}
%>
<%
    jspContext.setAttribute("outcome",fun(n));
%>